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Diffstat (limited to '.venv/lib/python3.12/site-packages/dns/ipv6.py')
-rw-r--r-- | .venv/lib/python3.12/site-packages/dns/ipv6.py | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/dns/ipv6.py b/.venv/lib/python3.12/site-packages/dns/ipv6.py new file mode 100644 index 00000000..4dd1d1ca --- /dev/null +++ b/.venv/lib/python3.12/site-packages/dns/ipv6.py @@ -0,0 +1,217 @@ +# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license + +# Copyright (C) 2003-2017 Nominum, Inc. +# +# Permission to use, copy, modify, and distribute this software and its +# documentation for any purpose with or without fee is hereby granted, +# provided that the above copyright notice and this permission notice +# appear in all copies. +# +# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES +# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR +# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT +# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + +"""IPv6 helper functions.""" + +import binascii +import re +from typing import List, Union + +import dns.exception +import dns.ipv4 + +_leading_zero = re.compile(r"0+([0-9a-f]+)") + + +def inet_ntoa(address: bytes) -> str: + """Convert an IPv6 address in binary form to text form. + + *address*, a ``bytes``, the IPv6 address in binary form. + + Raises ``ValueError`` if the address isn't 16 bytes long. + Returns a ``str``. + """ + + if len(address) != 16: + raise ValueError("IPv6 addresses are 16 bytes long") + hex = binascii.hexlify(address) + chunks = [] + i = 0 + l = len(hex) + while i < l: + chunk = hex[i : i + 4].decode() + # strip leading zeros. we do this with an re instead of + # with lstrip() because lstrip() didn't support chars until + # python 2.2.2 + m = _leading_zero.match(chunk) + if m is not None: + chunk = m.group(1) + chunks.append(chunk) + i += 4 + # + # Compress the longest subsequence of 0-value chunks to :: + # + best_start = 0 + best_len = 0 + start = -1 + last_was_zero = False + for i in range(8): + if chunks[i] != "0": + if last_was_zero: + end = i + current_len = end - start + if current_len > best_len: + best_start = start + best_len = current_len + last_was_zero = False + elif not last_was_zero: + start = i + last_was_zero = True + if last_was_zero: + end = 8 + current_len = end - start + if current_len > best_len: + best_start = start + best_len = current_len + if best_len > 1: + if best_start == 0 and (best_len == 6 or best_len == 5 and chunks[5] == "ffff"): + # We have an embedded IPv4 address + if best_len == 6: + prefix = "::" + else: + prefix = "::ffff:" + thex = prefix + dns.ipv4.inet_ntoa(address[12:]) + else: + thex = ( + ":".join(chunks[:best_start]) + + "::" + + ":".join(chunks[best_start + best_len :]) + ) + else: + thex = ":".join(chunks) + return thex + + +_v4_ending = re.compile(rb"(.*):(\d+\.\d+\.\d+\.\d+)$") +_colon_colon_start = re.compile(rb"::.*") +_colon_colon_end = re.compile(rb".*::$") + + +def inet_aton(text: Union[str, bytes], ignore_scope: bool = False) -> bytes: + """Convert an IPv6 address in text form to binary form. + + *text*, a ``str`` or ``bytes``, the IPv6 address in textual form. + + *ignore_scope*, a ``bool``. If ``True``, a scope will be ignored. + If ``False``, the default, it is an error for a scope to be present. + + Returns a ``bytes``. + """ + + # + # Our aim here is not something fast; we just want something that works. + # + if not isinstance(text, bytes): + btext = text.encode() + else: + btext = text + + if ignore_scope: + parts = btext.split(b"%") + l = len(parts) + if l == 2: + btext = parts[0] + elif l > 2: + raise dns.exception.SyntaxError + + if btext == b"": + raise dns.exception.SyntaxError + elif btext.endswith(b":") and not btext.endswith(b"::"): + raise dns.exception.SyntaxError + elif btext.startswith(b":") and not btext.startswith(b"::"): + raise dns.exception.SyntaxError + elif btext == b"::": + btext = b"0::" + # + # Get rid of the icky dot-quad syntax if we have it. + # + m = _v4_ending.match(btext) + if m is not None: + b = dns.ipv4.inet_aton(m.group(2)) + btext = ( + f"{m.group(1).decode()}:{b[0]:02x}{b[1]:02x}:{b[2]:02x}{b[3]:02x}" + ).encode() + # + # Try to turn '::<whatever>' into ':<whatever>'; if no match try to + # turn '<whatever>::' into '<whatever>:' + # + m = _colon_colon_start.match(btext) + if m is not None: + btext = btext[1:] + else: + m = _colon_colon_end.match(btext) + if m is not None: + btext = btext[:-1] + # + # Now canonicalize into 8 chunks of 4 hex digits each + # + chunks = btext.split(b":") + l = len(chunks) + if l > 8: + raise dns.exception.SyntaxError + seen_empty = False + canonical: List[bytes] = [] + for c in chunks: + if c == b"": + if seen_empty: + raise dns.exception.SyntaxError + seen_empty = True + for _ in range(0, 8 - l + 1): + canonical.append(b"0000") + else: + lc = len(c) + if lc > 4: + raise dns.exception.SyntaxError + if lc != 4: + c = (b"0" * (4 - lc)) + c + canonical.append(c) + if l < 8 and not seen_empty: + raise dns.exception.SyntaxError + btext = b"".join(canonical) + + # + # Finally we can go to binary. + # + try: + return binascii.unhexlify(btext) + except (binascii.Error, TypeError): + raise dns.exception.SyntaxError + + +_mapped_prefix = b"\x00" * 10 + b"\xff\xff" + + +def is_mapped(address: bytes) -> bool: + """Is the specified address a mapped IPv4 address? + + *address*, a ``bytes`` is an IPv6 address in binary form. + + Returns a ``bool``. + """ + + return address.startswith(_mapped_prefix) + + +def canonicalize(text: Union[str, bytes]) -> str: + """Verify that *address* is a valid text form IPv6 address and return its + canonical text form. Addresses with scopes are rejected. + + *text*, a ``str`` or ``bytes``, the IPv6 address in textual form. + + Raises ``dns.exception.SyntaxError`` if the text is not valid. + """ + return dns.ipv6.inet_ntoa(dns.ipv6.inet_aton(text)) |